In recent years, display devices such as liquid crystal display devices are used in various technical fields, and there is a demand of further improving the definition in the liquid crystal display devices. As high-definition progresses, there arises the problem of mixture of colors between pixels adjacent to each other, which emit different tones of colors. In liquid crystal display devices in which color filters are formed on a counter substrate, alignment error between the counter substrate and array substrate is the most significant cause for the color mixture. Under these circumstances, the technique of forming color filters on an array substrate is known. However, for a higher definition, such a simple technique of arranging color filters on an array substrate cannot fully solve the problem of the color mixture. For fringe field switching (FFS) display devices with higher definition, a technique for suppressing color mixture is known, in which the distance from an upper portion of a signal line to a bottom portion of a liquid crystal layer is set to a predetermined value or less.